Ask Ray - letters from April 2010

April '10

Q&A from Hemmings Muscle Machines

Storage Confusion
In HMM#70, July 2009, you explain to a reader about how to store his 2008 Dodge Challenger SRT8, but I have some questions. I have a 2010 Challenger that I want to store when not in use. Do I need to ''fog the cylinders'' like I used to with my older cars? Wouldn't covering the exhaust with a plastic bag as you advised keep the moisture in the system? Please let me know. I would like to keep and drive this car for a long time. Thanks.Scott Jarosz
Hamburg, MichiganThe purpose of covering the tailpipe openings along with the air intake is to keep moisture from entering the cylinder bores. A multiple-cylinder engine with the valvetrain functional will have at least one valve open somewhere. This creates a path for moisture to wick into the cylinder bores. That is why, if an engine is going to be stored for many years, it is a good idea to fog the cylinders with some sort of oil. But over time, the oil, too, will eventually run off. Thus, the reason for covering the intake and exhaust openings is not to save the exhaust system (it is stainless steel anyway), but to limit the amount of humidity entering the bores.My original response was to someone who planned to keep the car stored for many years without use. It seems that you do not want to do that. I got the impression that you are going to drive your Challenger in between idle periods. For this reason, I do not suggest fogging the cylinders, since it will not be that easy on an EFI engine. The intake manifold runners are very long and the ignition system is not readily disabled unless you pull some fuses. Also, the more you do to store the car, the less likely you are to use it. If it is just a matter of getting in and turning the key, you will drive it more.If my analysis of your intended use is correct, I would do nothing more than keep the gas tank full and put the Challenger in a garage for protection from the weather. Then enjoy it at every opportunity.Show me the Difference
I enjoy your articles. My question is, do the Chevy 305 stock block and the HO version share the same bore and stroke? Bob Starbile
Via e-mailThe non-performance and HO version of the 305 engine share the same bore and stroke; the major differences are in the cylinder heads, intake manifold, carburetor and camshaft profile. The 305 HO versions that were found in the early 1980s Camaro and Firebird were actually very strong runners for their time. As a matter of fact, they were faster than the TPI 350 engines when tuned properly.I do not believe that the engine block was any different, though I may be wrong. Those engines are now nearly 27 years old and much of the information has been homogenized into the generic 305 specifications. I do not believe that the HO version had better internal components, but would not be surprised if it had a steel crankshaft instead of cast iron. Chevy generally used steel crankshafts in truck engines and in many slightly warmed-over production applications. I am sorry that I could not be of more help.Trust but Verify
In HMM#70, July 2009, there is an article about Gene Werst's 1989 Pontiac Firebird Formula. According to the text, the 355-cu.in. small-block Chevy was estimated to be capable of producing 510-lbs.ft. of torque at around 2,700 RPM. I cannot help but be skeptical. A base-level 1970 Buick GS 455 produces 510-lbs.ft. at 2,800 RPM. Pontiac's 1970 GTO 455 produces 500-lbs.ft. at 2,700 RPM. I find it a little hard to imagine a bored-out Chevy 350--even one with a 6.0-inch connecting rod--matching the low-end grunt of two of the muscle car era's most legendary torque masters.John E. Martin
Via e-mailThough I never dyno'd the engine in question, I have built others of the same displacement that produced anywhere between 494- to 507-lbs.ft. of torque, though a little higher up, at around 3,100 to 3,400 RPM. I did not write that article and, while I believe the torque estimate is correct, I agree that the author misquoted me about the engine speed.Even given the higher engine speed, the numbers are impressive. The torque is the result of a 21-inch-long intake runner that the ACCEL Super Ram manifold uses along with proper timing of the valve events. Gene's engine also has 11.88:1 compression ratio and very good flowing cylinder heads with a minimal flow loss through the manifold. A great deal of work was done on the intake manifold runners so that they would not kill the cylinder-head flow. If my memory is correct, the cylinder heads on that engine flow around 275 CFM at 28 inches of water.When compared to the other engines I built, which were slightly different in combination, the horsepower range was between 416 and 497, depending on the camshaft grind and intake manifold style. Knowing this, I felt that 500- to 510-lbs.ft. was a good estimate for his 355. But if it makes you feel any better, I know that it will make at least 495-lbs.ft. all day long, and not with a ragged, on-the-edge tune that may be required for the 510 number. Thanks for questioning the results. I hope this answers your question.Missing a Shift
About a year ago, I purchased a 1970 Chevrolet El Camino and I love it. I have made some changes to improve its performance and appearance. It now has a 350 V-8 with a Weiand intake manifold and Edelbrock carburetor, headers and slightly warmer camshaft. When I purchased the car, I assumed that it had a Turbo 350 transmission. I attempted to have a shift improver kit installed, and was told by the mechanic that it actually has a THM 250C lock-up transmission.
Do you have any suggestions on how I can improve the performance without replacing the transmission? So far, I have not been able to find a kit that will work with the THM 250. The transmission seems to work okay, except shifts are a little on the slow side. Any suggestions will be greatly appreciated. Also, I love the magazine.Rhett Hanks
Huntsville, AlabamaTo the best of my knowledge, the THM 250C was based on the THM 350, with only minor external differences. That is why when you looked under your El Camino, you thought it had a THM 350. Though I'm not intimately familiar with the THM 250C, I believe that its major difference is the weaker parts when compared to the THM 350. Used with low-powered engines, the THM 250C had less mass and was part of General Motors' efforts to improve fuel economy.With this established, while a dedicated shift kit may not be offered for the THM 250C, I am quite sure a good transmission man will have no problem tuning the unit to your liking. The operative words here are ''a good transmission man,'' and not someone who simply knows how to replace parts. You state that the shifts are ''a little slow.'' I am not sure what you mean. Are they soft? Do they occur at too low an engine speed? Take too long to complete? If this is the case, then have the trans shop increase the line pressure for shift firmness and recalibrate the governor to get the shift RPM where it will best suit the engine. If the transmission works fine, I do not see any need to replace it with a THM 350 design.Once the transmission is correctly calibrated, you may want to consider examining the torque converter stall speed, especially since you installed a more aggressive camshaft. If the torque converter is excessively tight, the engine will feel very lazy at low speeds and around town. You will be surprised what an extra 200 to 300 RPM in the stall speed will do to wake up a combination.Pontiac Power
I have a stock 1963 Pontiac Catalina with 36,000 original miles. It is a four-door sedan with a 389 and single exhaust. It is the low-output engine with a two-barrel carburetor. My question is, what kind of easy engine mods can I do to get the horsepower up from 215 to around 270? I know people do headers, exhaust and a carburetor, but I am very new to engine work and would like some advice on companies or products. Thank you.Peter Manougians
Via e-mailMy parents had a 1963 Catalina four-door sedan with the same engine as yours. It was one of the smoothest, quietest engines I can ever remember experiencing. That Catalina was so quiet that my mother used to think that it stalled. With that said, and given the stated condition of your car, I would leave it stock. A virgin 1963 Pontiac is a rare find, and I would not want to be the one to alter it. But if you insist on stepping up the power, I can provide some suggestions.The first thing is to get the Catalina on a chassis dyno in its current state and tune. Get yourself a power number so you can assign a goal for your efforts. Just assuming that you want 270 horsepower does not mean you are going to achieve that result. Whatever power your engine makes now can probably be improved upon with a good tune-up and re-curve of the distributor along with a lower restriction muffler, while maintaining the single exhaust system.You may find that the state of tune is so weak now that after dialing everything in, you may get the feel you desire, but with a number that is lower than your expectations. My best advice to you is to chase the seat-of-the-pants feel and not a horsepower number. You will be much happier that way. If the car feels good to you, what difference does it make if it has less real power than you believe that you wanted?If the super-tune does not get you where you want, I would consider doing modifications in a stepped approach until the driving dynamics of your Pontiac satisfies you. The first step would be a conversion to a four-barrel carburetor and intake manifold. It would be nice if you could locate some factory parts, but if not, I suggest an Edelbrock Performer manifold (not the RPM series) and a small 450- to 500-CFM Edelbrock or Holley carburetor. The next step would be a dual exhaust system. The last modification would be a very mild camshaft swap that will not impact the idle quality or engine vacuum, but still provide more aggressive valve events.If I were a betting man, I would put my money on the super-tune with the car in stock form getting you the punch you want, while leaving your original car intact.Mustang Musings I recently purchased a beautiful 2005 Mustang GT with only 13,000 miles. The car has the manual transmission and was completely stock and garage kept; it even smelled new inside.
After a few weeks, I got used to the power and wanted more. I decided to install a high-flow exhaust and aftermarket fresh-air kit. The company that sold me the parts said that it would add about 20 to 30 horsepower at the rear wheels. I jumped at it. Luckily, I had the car checked on a Mustang-brand chassis dyno before I did the work (not in anticipation of making modifications, just for my own knowledge), and it produced 263 horsepower at the tires.
After installing the so-called speed parts, the car seemed lazy and not as crisp as before. I decided to chassis-dyno it again, but at a facility with a Dyno-Jet machine. My perception was correct: My Mustang lost 23 horsepower after spending almost $1,000 on the exhaust and fresh-air kit, with labor. Is this possible or is my pony a sick horse?Jack Greene
Wall, New JerseyI have had only one 2005 Mustang GT on a dyno. It was an automatic transmission press car and it produced 251 horsepower and 264-lbs.ft. of torque at the rear wheels. So the numbers you state for a manual transmission version, around 260 to 265 horsepower, are accurate. But as you did, you should always get a baseline run on your own car before starting any modifications.The Mustang-brand dyno is an eddy-current design, whereas the Dyno-Jet that I used is inertia-based and will probably show slightly higher numbers than the electric dyno. In this hobby, we have to remember that we are not racing or comparing dyno numbers, but the cars themselves. An enthusiast can get derailed by dyno or flowbench numbers that are not comparable. That is why I always suggest a baseline--all subsequent testing should be done at the same facility. But since your performance and dyno numbers are down, the decrease in power is real.With the quality control employed by Ford, there is little possibility that your engine has an internal problem. A shop that I have close ties to had an '05 Mustang that responded similarly to yours. It had a fresh-air kit and a cat-back exhaust installed, and lost about 20 horsepower.The cure was a re-flash of the engine management system. After that, the new parts added about 20 horsepower at peak (not across the operating range) over the stock value. I have also heard of other Mustangs and Corvettes responding the same way. The bad part about the re-flash is that it'll require you to use premium-grade fuel, eliminating the Mustang advantage of 300 flywheel horsepower on the cheap stuff.In many cases, stated power gains from performance parts are based on ideal conditions, which you may not have experienced. I've noticed also that many aftermarket cold-air kits for late-model Mustangs now are accompanied with some form of calibration update. Ford did a great job on the Mustang, and it is in optimized form as it leaves the Flat Rock, Michigan, assembly plant--but changing hardware may alter the parameters Ford's engineers used to establish the stock calibration. It now appears that your car will require a re-flash to handle the increased airflow. It's possible that some cars may respond without a re-flash if Ford modified the factory parameters as a running change. That may be the reason some units are more responsive to bolt-ons, while others drop horsepower without a recalibration.

This article originally appeared in the April, 2010 issue of Hemmings Muscle Machines.